The present invention relates generally to a clamp and, more particularly, to a fluid powered, sealed pin locating and clamping apparatus.
Powered clamps have been commonly used to secure workpieces, such as sheet metal automotive body panels, polymeric parts and the like in checking fixtures, gauging stations, welding stations, punching stations and other locations within a manufacturing environment. Many existing clamps are powered by hydraulic or pneumatic fluid pressure. For example, reference should be made to the following U.S. patents, which have been invented by Sawdon: U.S. Pat. No. 6,502,880 entitled “Pin Part Locator” which issued on Jan. 7, 2003; U.S. Pat. No. 6,378,855 entitled “Locking Pin Clamp” which issued on Apr. 30, 2002; U.S. Pat. No. 5,190,330 entitled “Powered Clamp with Parallel Jaws” which issued on Mar. 2, 1993 and U.S. Pat. No. 6,902,159 entitled “Sealed Pin Locating and Clamping Apparatus” which issued on Jun. 7, 2005; all of which are incorporated by reference herein.
Many of the previously known locating pin clamps include a mechanism which drives a finger or arm which extends outwardly from the pin and pulls down against the workpiece to hold the workpiece in place while operations such as welding and/or clinching take place. Additionally, some locating pin clamps include an aperture in the locating pin to allow the finger to extend and retract from the pin during operation. This aperture provides a path for contamination to enter into the mechanism. Because locating pin clamps are often used in harsh environments, locating pin clamp reliability may be a concern.
Furthermore, some of the known locating pin clamps release the workpiece if there is a loss of fluid pressure during clamp operation. It is desirable to prevent the clamping arm from opening and releasing the workpiece if a loss of fluid pressure were to occur. Prior constructions employing such a feature are disclosed in U.S. Pat. No. 5,871,250 entitled “Sealed Straight Line Gripper” which issued to Sawdon on Feb. 16, 1999 and U.S. Pat. No. 5,853,211 entitled “Universal Gripper” which issued to Sawdon et al. on Dec. 29, 1998. These patents are also incorporated by reference herein.
In accordance with the present invention, a clamp includes a body, a lead pin moveable relative to the body and an actuator supported by the body. The actuator is axially moveable between an extended position and a retracted position. The actuator includes a camshaft drivingly coupled to the lead pin. Axial movement of the camshaft causes the lead pin to rotate between a first positioned aligned with a first longitudinal axis and a second position aligned with a second longitudinal axis laterally offset from the first longitudinal axis.
As another feature of the present invention, the clamp includes a body, an actuator moveably supported by the body, and a clamping member drivingly coupled to the actuator. The actuator includes a pair of rollers, each roller being positioned within one of two grooves formed on an axially and rotatably moveable camshaft. Each groove includes a plurality of detents. The clamping member axially translates and rotates between an extended position and retracted position in response to movement of the actuator. The rollers are positionable in engagement with the detents to restrict movement of the clamping member in the absence of force being provided by the actuator.